Traditional electrophotographic (EP) devices have a spinning polygon mirror that directs a laser beam to a photoconductor, such as a drum, to create one or more scan lines of a latent to-be-printed image. Recently, however, it has been suggested that torsion oscillator or resonant galvanometer structures can replace the traditional spinning polygon mirror to create scan lines in both the forward and reverse directions (e.g., bi-directionally) and increase efficiency of the EP device. Because of their MEMS scale size and fabrication techniques, the structures are also fairly suggested to reduce the relative cost of manufacturing. Unfortunately, scanning in two directions adds a measure of complexity to image referencing since reference points need occur for each of the forward and reverse scans at opposite ends of the printed page and the slightest of deviations amplifies print image imperfections. Also, EP device parameters, such as beam sensor signal delays, optical component alignment, and galvanometer or oscillator scan profile nonlinearity must be measured and accounted for.
Accordingly, there exists a need in the art for calibration techniques for bi-directionally scanning EP devices. Particularly, there are needs by which the print alignment is accounted for at one or more of the stages of manufacturing, servicing or end-user operation. Naturally, any improvements should further contemplate good engineering practices, such as relative inexpensiveness, stability, low complexity, ease of implementation, etc.